Beam-compass.



No. 812,322. PATENTED PEB. 18, 1906.

T. N. BADGEB..

Y BEAM COMPASS. APPLICATION FILED IT-IL Y 17', 1905.

PATENT OFFICE.

THOMAS N. BADGER, OF OAKLAND, CALIFORNIA.

BEAM-COMPASS.

Specification of Letters Patent.

Patented Feb. 13, 1906.

Application led July 1'7, 1905. Serial No. 269,925.

To LZZ whom it may concern:

Be it known that I, THOMAS N. BADGER, a citizen of the United States, residing in Oakland, in the county of Alameda and State of California, have invented new and useful Improvements in Beam-Compasses, of which the following is a speciiication.

This invention relates to an improved compass ofthe kind or description used by draftsmen for describing arcs of large diameter and commonly known as a beam-compass.

The essential features of my improved instrument are a thin beam adapted to lie lat upon the paper and an adjustable holder capable of supporting or holding` a pen or pencil in a position generally perpendicular to the surface of the paper at one side or edge of the beam, the said holder being movable upon the beam and having means Jfor clamping or lixing it at any desired point in the length of the beam, together with a means for holding one end of the beam at the center from which the arc or circle is to be struck and around which the beam is freely movable.

The following description explains at length the nature of my said invention and the manner in which I proceed to construct and produce an instrument of the kind in accordance threwith, the accompanying drawings being referred to as a part of this specification.

In the said drawings Ihave illustrated what I consider to be the best construction and embodiment of the several features of my invention.

Figure l illustrates one form or style of. instrument embodying my invention, in which a steel tape-measure of the kind used by architects and surveyors is employed for the beam7 and the tool-holder is detachable as well as adjustable on the tape, thereby enabling the measure to be used in the ordinary way as a tape-line by unshipping the holder and also to be used as a beam-compass to describe arcs or circles of large dimensions. Fig. 2 is a top view of a portion of the beam, showing the same divided into inches and tenths and-formed of a thin flat strip band or bar of metal which is adapted to lie iiat on the paper, but is not sufficiently flexible to be wound on a reel. Fig. 3 is a side elevation oi the tool-holding clamp in position on the beam. Fig. 4 is a front view of Fig. 3. Fig. 5 is a top view of Fig. 4. Fig. 6 is a longitudinal section of the tool-holding clamp. Fig. 7 is an elevation of the tool-holder made detachable from the clam Figs. 8, 9, and 10 'are details of a modi cation in which the clamp and the post or tool-holding part are cast 1n one piece and the tool-holder is a separate piece having a socket for attaching a ruling-pen or a pencil-point.

Referring to these parts by letter, A indicates a tape or thin strip of metal such as is used for steel tape-lines, and B is a reel or case of well-known construction in which the tapeeline is coiled and inclosed when not in use. This tape-line differs from the tapeline heretofore made, first, in having its face divided into inches and tenths and, secondly, in having the division-marks scored or graved in the metal. Heretofore it has been the practice to etch the division-marks or lines on these steel tapes; but so far as I am aware a steel tape has never been made with the division-marks scored in the metal. Tapes with the etched marks, while suliiciently ac curate for ordinary work, are not well adapted for use as a beam in connection with my adjustable clamp, where exact measurements and distances on the paper are necessary, as in engineering and topographical work; but by providing the tape with scored divisionmarks all the accuracy of a scale is secured.

C is a clamp composed of a block of metal having a slit or aperture 3 extending longitudinally through it from end to end, and 4 is a movable clamp composed of a thin plate inserted in the aperture and to which pressure is applied from above by a clamp-screw D, workin@ through a threaded hole in the top of the block, the tape-line being inserted between the plate 4 and the bottom of the aperture beneath it. When the clamp 4 is raised, the end of the tape may be readily passed through the block.

E is a post standing perpendicularly upward from the block and either permanently attached thereto or made integrally with it or else detachable from the block.

F is a tool-holding piece having a socket to fit the end of the post and provided with a clamp-screw 5 for securing it in place, and G is a spring-tongue secured to the piece F, from which it extends downwardly and in a generally perpendicular position. A socket in the end of this spring-tongue receives and holds the pen I or a pencil-holding point L.

II`is an adjusting-screw working through a threaded socket on the lower end of the s ring-tongue and arranged to bear against t e post E as a means of adjusting the Work- IOO ing point carried by the end of the spring(- tongue-that is,the pen or the pencil-so as to change the working position of theI same, In one form the post E is made separable anddetachable` from the block O,.in which case a fastening means is provided on the block7 such as a screw K. This construction is illustrated in Figs. 3, 6, and 7 of the drawingsi. In another Way the post is formed integrally. with the block, as shown in Fig. 8 of the drawings. Y

In describing an arc from a giyen center the beam is held at one end Hatthe center by fixing a needle-point N, kas ,shown in `Fig. lJIA into the drawing-.board through a small hole madein the steel tape or beam A. 'Ihishole y fm is located on the Zerofmark of the beamhso that `the required measurements are accu,-Vv

rately read and determined from that pointfi Having thus described my said' ,iI1YQntion,.

I what I claim, and desire to secure byLetters Patent,isi Y. :1 mi

1. Ina beamcompass,the combinationof a beam7 a sliding detachable clampproyided with a iiat bearing-surface arranged tolie on i and slide over, the surface tobe marked,V a post extending upward from the clamp7 a 2. Ina beam-compass, vthe combination of ya flexiblebeamh adetachable clamp arranged to beadjusted alongthe said beam, a perpen-A dicularly arrangedpost `mounted" on the lclarnpfav tool-'holding piece connected to the 'outer end of the postdv a drawing instrument;y

anda spring-tongue for connecting the drawlng instrument to the toolfholdin pie`ce,"the

said post, 4tool-holding piece and" rawing instrumentbeing separabley from each other, substantially as set forth.

In testimony whereof I have hereunto set" name to this specification' in the presence of two subscribing witnesses.

THOMAS N. BADGER.

Witness'e'sf p HARRY J. LAsi,

EDWARD E. OsBoRN. 

